Gender and Age Disparities in Public Health Crisis Disruptions to Cross-Border Mobility: A Causal Analysis of Daily Flows Between Shenzhen and Hong Kong

Cross-border mobility (CBM) is highly sensitive to policy shocks during public health crises, yet its behavioral and demographic dynamics remain poorly understood. CBM disruptions can be conceptualized as differentiated responses to non-pharmaceutical interventions (NPIs) across demographic groups in integrated cross-border systems. Focusing on the Shenzhen–Hong Kong cross-border mobility corridor, causal evidence shows that NPIs generate both immediate and uneven mobility contractions. These responses are structured along gender and age lines: younger individuals and males exhibit more elastic and rapid behavioral adjustments, whereas females demonstrate greater stability and faster recovery. In contrast, older adults show limited initial responsiveness but prolonged recovery, indicating persistent structural constraints. These findings identify vulnerable populations and provide empirical evidence for designing targeted, equitable border management and transportation policies in highly integrated regions during future public health crises.